ID   VE4_HPV5B               Reviewed;         240 AA.
AC   P26550;
DT   01-AUG-1992, integrated into UniProtKB/Swiss-Prot.
DT   18-JAN-2017, sequence version 2.
DT   29-SEP-2021, entry version 39.
DE   RecName: Full=Protein E4;
GN   Name=E4;
OS   Human papillomavirus type 5b.
OC   Viruses; Monodnaviria; Shotokuvirae; Cossaviricota; Papovaviricetes;
OC   Zurhausenvirales; Papillomaviridae; Firstpapillomavirinae;
OC   Betapapillomavirus.
OX   NCBI_TaxID=10599;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1649510; DOI=10.1016/0042-6822(91)91013-7;
RA   Yabe Y., Sakai A., Hitsumoto T., Kato H., Ogura H.;
RT   "A subtype of human papillomavirus 5 (HPV-5b) and its subgenomic segment
RT   amplified in a carcinoma: nucleotide sequences and genomic organizations.";
RL   Virology 183:793-798(1991).
CC   -!- FUNCTION: Contributes to multiple aspects of the viral life cycle
CC       including viral genome amplification, suppression of suprabasal cell
CC       differentiation and egress of newly formed virions. Induces host cell
CC       cycle arrest at the G2 phase by associating with and preventing the
CC       nuclear entry of host CDK1/cyclin B1 complexes. Inhibits cellular DNA
CC       replication by preventing loading of host replication licensing
CC       proteins MCM2 and MCM7 onto chromatin. Within the cytoplasm, associates
CC       with host kinase SRPK1, a splicing factor regulator, and inhibits its
CC       activity. Therefore, E4 favors expression of late viral transcripts by
CC       inhibiting SRPK1-mediated phosphorylation of host serine-arginine (SR)
CC       proteins that have critical roles in mRNA metabolism. Late in the
CC       infectious cycle, E4 also acts to diminish the integrity of the
CC       keratinocyte by disrupting the keratin cytoskeleton and inducing
CC       apoptosis through alteration of mitochondrial function to facilitate
CC       egress of the newly formed virions. {ECO:0000250|UniProtKB:P06922}.
CC   -!- SUBUNIT: Assembles into oligomeric complexes. Interacts with host CDK1.
CC       Interacts with host SRPK1; this interaction may favor expression of
CC       late viral transcripts. Interacts with host cytokeratin components KRT8
CC       and KRT18. {ECO:0000250|UniProtKB:P06922}.
CC   -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000250|UniProtKB:P06922}.
CC       Host nucleus {ECO:0000250|UniProtKB:P06922}.
CC   -!- PTM: Phosphorylated by host ERK. The phosphorylation triggers a
CC       structural change that enhances keratin binding and protein stability.
CC       {ECO:0000250|UniProtKB:P06922}.
CC   -!- MISCELLANEOUS: The major E4 form is first synthesized as an E1^E4
CC       fusion protein from spliced E1^E4 transcripts, such that the first few
CC       amino acids of the E4 protein are derived from the N terminus of E1.
CC       {ECO:0000250|UniProtKB:P06922}.
CC   -!- SIMILARITY: Belongs to the papillomaviridae E4 protein family.
CC       {ECO:0000305}.
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DR   EMBL; D90252; BAA14296.1; ALT_SEQ; Genomic_DNA.
DR   PIR; C40480; W4WLB5.
DR   SMR; P26550; -.
DR   Proteomes; UP000007669; Genome.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0039592; P:suppression by virus of G2/M transition of host mitotic cell cycle; IEA:UniProtKB-KW.
PE   3: Inferred from homology;
KW   Early protein; Host cytoplasm; Host G2/M cell cycle arrest by virus;
KW   Host nucleus; Host-virus interaction;
KW   Modulation of host cell cycle by virus; Phosphoprotein.
FT   CHAIN           1..240
FT                   /note="Protein E4"
FT                   /id="PRO_0000133258"
FT   REGION          1..204
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        1..20
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        21..40
FT                   /note="Pro residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        85..107
FT                   /note="Pro residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        164..182
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ   SEQUENCE   240 AA;  25032 MW;  33617682BBC84E1C CRC64;
     MTDPNSKAPR LQGRQEDKQT QTPPPRPPPP PQPPLTPRPD SSPHQNSHNK PKPEEEGTDG
     GPPASQGDRK RSKGDQGPDT GPGLGPGRAP SPKPTPLGPP PGPGPRRSAR LGPLQADRDP
     GEGPQVPAEG EVEGHPGGDQ GHPPPTPPAP HNGHSGHGPK VQQPEGPEGR EGHEEGAVGG
     DCGDEEGHPP PPPPPTNGHE GGLLSSVASL LVKWEGHFDQ LVQSIQDDLE DYWKKLATPQ